
on the Terra Ponderofa, &c. 309 
E. This earth, after expofure to a white heat for one hour, 
became cauftic, and made lime-water, fimilar in properties to 
to that mentioned at § Ift. E. 
K. Some of the part not acted upon by the nitrous acid iF, 
difiolved entirely by boiling in highly concentrated vitriolic 
acid, and wholly feparated again by the affufion of water. More 
Water was added, and the whole was boiled again; but the fil- 
tered liquor gave no figns of precipitation upon the moft liberal 
addition of mild fixed vegetable alkaly. 
CON; © EUS: OuN) Ss. 
It appears, therefore, that 100 parts of Derbyfhire cauk 
contain. 
Marmor metallicum = - 9955 
Calciform iron. = - 5: 
100 
And it is probable, that the redder pieces contain a little more: 
iron. 
Bee et oN! ay 
Terra ponderofa vitriolata. 
Variety, radiated Cauk. 
Gypfum cryftallifatum capillare. CronstepT Min,. 
pie R. 
From Pennely by he Bog, near Minfterley, in Shropthire, 
_ fifteen miles from Salop, on the road to Montgomery. 
Mor €° 
